Means for effecting the relative movement of a centrifugal separator basket and pusher



March 2, 1965 B. G. cox 3,171,309

MEANS FOR EFFECTING THE RELATIVE MOVEMENT OF A CENTRIFUGAL SEPARATOR BASKET AND PUSHER Filed April 30, 1962 5 Sheets-Sheet 1 INVENTOR. awn 0 6 5&1

B. G. COX

March 2, 1965 3,171,809 MEANS FOR EFFECTING THE RELATIVE MOVEMENT OF A CENTRIFUGAL SEPARATOR BASKET AND PUSHER Filed April 50, 1962 3 Sheets-Sheet 2 FnD(Ixm II mmDmwuml l N OE INVENT OR.

NO. 5 :2 0M

March 2, 1965 a. G. cox 3,171,809

MEANS FOR EFFECTING THE RELATIVE MOVEMENT OF A CENTRIFUGAL SEPARATOR BASKET AND PUSHER United States Patent 3,171,809 MEANS FGR EFFECTING THE RELATIVE MOVE- MENT OF A CENTRIFUGAL SEPARATOR BASKET AND PUSHER Bradley G. Cox, Saginaw, Mich, assignor to Baker Perkins Inc, Saginaw, Mich, a corporation of New York Filed Apr. 30, 1962, Ser. No. 191,231 16 Claims. (Cl. 21il376) This invention relates generally to centrifugal machines and more particularly to certain novel and useful improvements in machines of the type wherein rotating and relatively reciprocating inner and outer shafts are employed for revolving and relatively reciprocating a separating basket and separating basket pusher or scraper. The present application'is a continuation-in-part of application, Serial No. 6,930, filed February 5, 1960, and now abandoned.

Hydraulic drive assemblies for reciprocating such an inner shaft within an encircling outer shaft, while the inner and outer shafts revolve as a unit, have been suggested in which a pilot valve is disposed diametrically or transversely within an integrated inner shaft piston for controlling the movement of the piston in an outer shaft cylinder. While such a construction is an improvement over prior art machines in which the hydraulic control was disposed externally of the inner and outer shaft assembly, the construction has some definite limitations. In order to direct the flow and discharge of high pressure hydraulic fluid to opposite ends of the inner shaft piston in the volume which is required, such a pilot valve must have a number of sufiiciently spaced lands of adequate width to stand up under the pressures employed and the piston housing the valve is thus required to be of considerable length. Accordingly, the diameter of the piston must be of a size to accommodate the pilot valve lengthwise in such a design and considerable power is required to move a piston of the diameter required in its reciprocatory stroke. Also, the design suggested did not lend itself to the use of anti-friction shaft support bearings and further because of design limitations the stroke of the inner shaft piston was not variable as desired.

One of the prime objects of the present invention is to design an integrated inner and outer shaft piston and cylinder assembly of the character described in which the fluid distributing and piston shifting pilot valve can be axially disposed and in which it is assured 'of being subjected to differential pressures at all times so that there is no possibility of the pilot member reaching a condition of hydraulic balance and becoming inoperative,

A further object of the invention is to provide an integrated assembly of this type in which means within the assembly but outside the cylinder chamber operates automatically to control the movement of a piston shifting pilot valve member.

Another object of the invention is to provide an assembly of the character described of a design wherein the pilot valve member is axially disposed within the inner shaft piston so that the inner shaft piston can accordingly be of less diameter. It is estimated that to obtain the same frequency and length of stroke at a given hydraulic pressure a piston unit which can employ an axial pilot valve member need be only approximately one third the diameter of a piston employing a diametrically arranged pilot valve member and, as a consequence, a considerable saving can be effected in the size of pump employed and in the material used to fabricate the parts.

A further object of the invention is to provide an assemly as described which lends itself to the use of antifriction bearings and employs the fluid discharged from the ends of the pilot valve to lubricate the bearings.

A further object of the invention is to provide a revolving and relatively reciprocable inner and outer shaft assembly in which the means provided for assuring a differential pressure at the ends of the pilot valve member maintains an exhaust line from the ends of the pilot valve open at all times and tends to prevent leakage at high pressures, the said means also functioning as a result to cushion the operation of the valve such that the high pressure lines are not subjected to undue shocks.

A further object of the invention is to design an assembly of the type described wherein oil pressure is continuously supplied to the working parts by a continuously operating pump.

Another object of the invention is to provide an assembly so designed that the length of stroke can be readily adjusted to suit the operation and material being centrifuged and in which the shaft piston can, by means of a simple adjustment, be operated independently of the hydraulic system pressure on its return stroke by the pressure of the material caking on the separating basket.

Another object of the invention is to provide an assembly of the character described in which the inner shaft extends beyond the outer shaft cylinder, the supply and exhaust system to the ends of the pilot valve is independent of any pilot valve chamber, and the means for controlling the pilot valve and for regulating the stroke of the piston is integrated therewith externally of the cylinder.

Other objects and advantages of the invention will be pointed out specifically or will become apparent from the following description when it is considered in conjunction with the appended claims and the accompanying drawings, in which:

FIGURE 1 is a partly sectional, side elevational view of a centrifugal machine of the character described, certain of the elements of the basket or cage end structure being omitted in the interests of simplicity of disclosure;

FIGURE 2 is an enlarged, longitudinal, fragmentary, sectional view of the left or rear end of the machine shown in FIGURE 1, illustrating the inner shaft piston in a position in which it has just completed its movement from right to left and the piston-shifting valve in a position in which it has just begun moving from right to left but has not yet reversed the inner shaft piston;

FIGURE 3 is a similar view showing the inner shaft piston in a position in which it has just completed its forward stroke from left to right and the piston-shifting valve in a position in which it has already commenced moving from left to right but has not yet reversed the inner shaft piston, the support housing and certain other parts being omitted in the interests of clarity;

FIGURE 4 is a transverse, sectional view taken on the line 4-4 of FIGURE 2 and particularly illustrating the construction of the slide sleeve which controls the pistonshifting valve.

Referring now more particularly to the accompanying drawings for the disclosure of a preferred embodiment of the invention and, in the first instance, to FIGURES 1 and 2, the centrifugal machine is shown as comprising a shaft supporting, oil reservoir housing 10 which is provided with bearing support members 11 and 12. The bearing support 11 may be supported by the housing 10 from a flange portion 13 having a section 14 which is bolted to the bearing support 11 by bolts 15 and the bearing support member 12 at the right end of the housing can be supported by members 16 or in any acceptable manner.

Each of the bearing support members 11 and 12 are recessed as at 17 and 18, respectively, to receive a conventional anti-friction roller bearing 19 which, as usual, comprises an outer race 19a, ball members 191), and an inner race 19c. Supported by the bearings 19 is the revolving shaft assembly S, which includes an outer, en-

circling, tubular shaft generally designated having an enlarged, piston receiving cylinder portion 21 integral therewith, and an innershaft member generally designated 22 whichhasa slightly enlarged piston section 23 integrated therewith and received within the cylinder 21..

A tubular outer shaft section 24 bolted to the cylinder section 21 as by bolts 25 and forming the left end of the encircling outer shaft 20 is driven by a pulley member 26 keyed thereon as at 26a and the inner shaft 22 is, in a manner to become apparent, adapted to revolve with the outer shaft 20 while reciprocating within it. 'Belts 27 connect with an electric motor in the manner of Patent No. 2,899,065 which shows a centrifugal machine of the same general construction. The front section 2001 of the tubular, outer shaft 20 is slotted as at 28 to receive a key 29 fixed to the front section 22a of inner shaft 22 which insures rotation of the shaft 22 with the shaft 20 .and it will be seen that the slot 28 is axially elongate relative to the key 29 so that reciprocation of the shaft 22 relative to the shaft 20 can occur. 7

As in the aforementioned patent, a centrifugal basket 30 is fixed to the front end of, the outer shaft 20 by means of a nut member 31 and this annular basket or cage is provided with expressing ports 32 in the usual manner. Fixed to the right end of the inner shaft 22, by means of a nut 33, is the pusher member 34 and, as in the patent mentioned, a predraining funnel 35 may be connected to circumferentially spaced lugs 36 on the reciprocating scraper member 34 so that ports 37 and 38 in the respective members lead to the rear of the pusher 34 and ports 39 in the basket 30. The radial space between the flange 35 of the slurry supplying funnel and the annular pusher disk 34 provides a substantially annular passage 40 broken only by the lugs 36 through which the slurry'is discharged to the basket 32 in the manner of the aforementionedpatent, which is herewith incorporated by reference, for any disclosure which may be desirable. A Wet housing 41 is provided to receive the liquids expressed through ports 32 and 39 and convey them to a suitable, place of discharge.

The invention is concerned with the manner in which the inner and outer shafts 22 and 20 are driven by the 'hydraulic fluid which is pumped by a conventional sucvided in the inner peripheral wall ofmember 11 which communicates with ports 48 in the outer shaft section 24. It will be seen that the member 24 is internally bored as at 24a to receive the left or rear end of an inner shaft section 49 which also forms a part ofthe inner shaft piston assembly and is bolted as at 50 to the piston section 23.

Received within the bore 24a is a slide sleeve control member generally designated 51 which will be later described in detail and the outer shaft member 24 also has a bore 52 communicating with the bore 24a into which the ports 48 lead, and a bore 53 extending rearwardly therefrom. I

In the drawings the solid line arrows indicate the pressure paths to the piston portion 23 of the inner shaft '22 and to the flow-distributing and piston-shifting pilot valve generally designated 54 which is reciprocably mounted in an axial bore or cylinder 55 within piston section 23, and

the brokenline arrows indicate the exhaust paths to the reservoir 42. These paths will be traced presently when the operation of the unit is describedin detail.

It will be seen that the rear endsection 49 of piston carrying shaft 22 is reduced as at 56 and isprovided with a threaded bore 57 which receives a rearwardly extending, threaded .rod member 58 of some length. The rod 58 extends rearwardlyrin'to the bore 53in outer shaft section 24 and mounts a sleeve member '59 which is front end portion of sleve 59 to leave an annular passage 63 therebetween which permits passage of the fluid from the rear end of the chamber '62 formed by bores 52 and 24a. As will be seen from an inspection of FIGURE 4, the inner peripheral wall of the control member 51 is broken only by a plurality of circumferentially spaced positioning lugs 64 which between them define fluid pass-' ing ports 65. Thus, since the diameter of the inner peripheral wall of member 51 is also somewhat greater than the diameter of the reduced rear end 56 of inner shaft section 49 to define an annular passage '66 therebetween, fluid is always free to pass through the control member 51 to a port 67. through the reduced portion 56 of the inner shaft section 49. The control sleeve 51 is also annularly grooved to provide a passage 68 communicating with exhaust ports 69 in the encircling shaft section 24, which in turn communicates with an annular chamber 70 between the bearing 19 and the adjacent wall of bearing support member 11. As will be later explained in detail, in all positions of the piston 23 either the front or rear end of pilot valve 51 is open to passage 68.

Extending axially through much of the inner shaft section 49 from the port 67 is a port 71 which communicates with a longitudinally extending port 72 in the piston section 23 of inner shaft 22 and leads to an annular passage 73formed by grooving the peripheral wall of the pilot valve member 54. The passages 46, 47,48, 62, 63, 65, 66, 67, 71, and 72 in effect comprise a main supply channel which in all positions of the various parts supplies fluid under a pressure which may be in the neighborhood of 1000 psi. or greater to the pilot piston 54 for distribution to one end of the cylinder section 21 of the outer shaft 20 or the other. Passage 75 in the piston section 23 leads to the right or front end of the cylinder section 21 from the annular space 73, and passages 76 and 77 in the piston sections 23 and 49, respectively, lead to the left end of the cylinder section 21. It will be 0 seen that thepilot valve 54 has a central recess 78, closed by a plug 79, at its .right end and. communicating by means of ports 80 with an annular groove 81 provided .in the rear end of the pilot piston 54 and communicating in some positions of the valve 54 with passage 76. The grooves 81 and 73 define between them a land 82, and the groove 73 and a front annular groove 83 similarly define a land 84 between them. Ports 85 communicate the pilot central passage 78 with the annular passage 83, as shown. 7 At its frontencl the pilot valve 54 has a projection 86 receivable within a recess 87 in the inner shaft section .49 to cushion the reciprocation of the pilot valve 54. Likewise, the plug 79is receivable within the passage 88 leading to the front end of the pilot valve bore 55 and functions similarly to cushion the stroke. Discharge from, the fluid distributingvalve 54 ,occurs through a passage 89 in the inner shaft piston section 23, which communicates with the discharge passage '83 at one end and with a discharge'port 90 in the cylinder portion 21 of the outer shaft 20. As has been noted, it is the pilot piston 54 which operates to shift the piston of shaft22 by distributing the fluid pressure alternately to the front and rear ends of the cylinder of shaft 20 and in order to accomplish shifting of the piston it is also necessary that the valve 54 be shifted axially or longitudinally. The ports which in the outer shaft section a. Ports 94 in the shaft section 213a communicate with an annular groove 95 provided in the inner shaft section 22a, and ports 96 in the inner shaft section 22a communicate the passage 95 and the passage 83 leading to the front of the pilot valve chamber 55. At the opposite end of the pilot valve chamber 55 a port 97 in the inner shaft section 49 leads from the cushioning recess 87 to an annular groove 98 in the section 49, and a passage 99 in the outer shaft section 24 communicates the groove 98 and the annular passage 68 formed by grooving the control sleeve 51. Groove 68 forms front and rear lands 100 and 109a on the control sleeve 51 which in one position (FIGURE 3) are disposed forwardly of the passages 91 and 99 respectively and in the other position (FIGURE 2) are disposed rear- Wardly of passages 91 and 99, respectively. A port p in land 1% permits contact of the hydraulic fluid which may be under a pressure of 800-1000 p.s.i. with the side of chamber 63 to provide a braking force which prevents drifting of sleeve 51. This is very important to the successful operation of the machine since in practice it was found the control sleeve 51 had a tendency to drift.

A cap member 101 is removably threaded, as at 192, in the outer shaft section 24 to provide ready access to the nut 61 and sleeve 59, and it will also be seen that a cap 193 is provided for the housing section 13 and is secured thereto by bolts 104 or in any other acceptable manner.

At the front end of the cylinder section 21 a passage 105 communicating with the front end of the piston chamber and with a passage 106 is shown blocked by an adjustable screw member 107 disposed in a threaded passage 108. Plainly, the screw member 107 may be adjusted axially of the passage 108 to permit bleeding of the fluid from the front end of the chamber through passage 106 in the degree desired or may be removed from passage 10%.

For a detailed description of the operation of the assembly I refer first of all to FIGURES 1 and 2, wherein the piston section of the inner shaft 22 has just completed its movement to the left so that pusher 34 is in rearward position and piston-shifting and fluid-distributing valve 54 has just begun to move to the left. The solid line arrows identify pressure paths as noted and the broken line arrows identify exhaust paths. In FIGURE 2 the pressure fluid is supplied from the continuously operating pump 43 to line 45 and to the distributing valve 54 via passages 46, 47, 48, 62, 63, 65, 66, 67, and 71. The receiving chamber of valve 54 is the annular groove 73 which in FIGURE 2 communicates with passage 75 leading to the front end of cylinder section 21 so that the force of the hydraulic fluid is applied to move the piston section 23 rearwardly. Discharge of the fluid from the rear or left end of the piston in FIGURE 2 at this time is through the passages 77, 76, S1, 89, 78, 85, 83, 89, and 91). It will be noted that the passages 76 and 75 are not fully opened and this is because the pilot piston 54 has commenced to move to the left or rearwardly to a position in which it will shift the piston section 23 forwardly. The passage 91 is accordingly opened to the port 67 in the rear end 57 of inner shaft section 49 and leads to passages 93, 94, 95, 96, and 88 to deliver the oil which forces the pilot valve 54 rearwardly. The fluid at the left end of the pilot piston 54 is discharged through passages 97, 98, 99, 68, 69, 7t and out through bearing 19 so that it lubricates the bearing as it proceeds. A bleed line 109 is also provided so that not all of the exhaust fluid need pass through the bearing 19.

In FlGURE 3 the piston section 23 has just completed its movement to the right or forwardly and the valve 54 has just begun moving to the right to reverse the piston, but has not yet done so. When the piston was at the left or rear end of the cylinder section 21 in FIGURE 2, the control slide 51 was in its rearward or most leftward position. However, when piston section 23 moved to the right to the forward position in which it is shown in FIGURE 3, the sleeve 59 on rod 58 which is threaded in the rear end 56 of the piston section 49 engaged the lugs 65 of the control sleeve 51 during forward movement of the piston section 23 and moved the control slide 51 forwardly to a position in which the land 1% of control slide 51 was forward of the passage 91 and the land a was forward of the line 99. In this position (FIGURE 3) of pilot piston control sleeve 51 the line 99 is open to the passages 46, 47, 48, and 62 and delivers pressure fluid to the passages 99, 98, 97, and 87, so that move ment of pilot valve 54 to the right is commenced to reverse the piston section 23. The front end of the pilot valve chamber 55 is exhausted, as shown in FIGURE 3, through passages 88, 96, 95, 94, 93, 92, 91, 68, 69, 70, and bearing 19.

At this time pressure is supplied to left or rear end of piston section 23 through passages 46, 47, 48, 62, 63, 64, 66, 67, 71, 72, 73, 76, and 77. Discharge of oil from the front end of cylinder section 21 is through passages 75, 83, 89, and 91). When the lands 82 and 84 have moved forwardly sufiiciently to be disposed forwardly of the passages 76 and 75, respectively, so that passage 73 communicates with passage 75, and passage 76 communicates with passage 81, the piston section 23 will commence to return to the position in which it is shown in FIGURE 2. During its travel, the reduced rear end section 56, which is a part of the inner shaft section 49, engages the control sleeve 51, lugs 65, and pushes the control sleeve 51 rearwardly to the position shown in FIGURE 2 in which land 1%- is rearward of passage 91 and land 100a is rearward of passage 99. As piston section 23 nears its complete return to the left, the valve 54 has already commenced to shift leftwardly.

Plainly it is the control sleeve 51 which initiates movement of the pilot valve 54, and the pilot valve 54 in turn shifts the piston in the cylinder 21. The length of stroke of the piston of shaft 22 is accordingly governed by the axial position of sleeve 59, which can be adjusted to engage the lugs 65 sooner or later and, accordingly, to move the control sleeve 51 forwardly earlier or later, thereby to shift the piston section of shaft 22 earlier or later. With some materials a shorter stroke is desired than with others and removal of the cap 101 to provide access to the nut 61 and sleeve 59 for adjustment of sleeve 59 is a simple matter.

In the system disclosed the various parts are always in a condition of hydraulic imbalance and accordingly various parts are never stopped by equal and opposite pressures. The exhaust ports 69 and 70 are open at all times to one of the lines 91 or 99 so that any leaking takes the path of least resistance to the outside atmosphere and does not get into the other ports where it could possibly create a hydraulic balance.

In some instances it may be desirable to power the piston assembly of shaft 22 only on the forward stroke and permit the pressure of the material building on the basket 31 between the funnel 35 and pusher 34 to return the plunger 34, as in the aforementioned patent. This is readily accomplished by removal of the threaded plug 107. In a case where some hydraulic fluid power is desired on the return stroke, adjustment of the plug 107 permits ready adjustment of the force with which the piston section 23 is returned. It does not, of course, require nearly as much power to return the pusher 34 as it does to push it forwardly.

The instant design is believed to lend itself particularly to the employment of the left roller bearing 19 in FIG- URE 1, which takes the full load of the inner and outer shaft assembly at the left end of the machine. The bore of the support member 11 (FIGURE 2) is not then required to bear the load and the seals 110 can eifectively accomplish their purpose.

Because the inner shaft 22 and outer shaft 20 extend leftwardly beyond the cylinder section 21 in the manner 7 disclosed, it is possible to provide a differential pressure on the inner shaft 22 which cushions the shock on the lines at the rear limit of the pistons stroke. In machines of this type using a high pressure fluid (in the neighborhood of 1000 psi.) the pressure reaches a peak at the rear end of the stroke when the pusher 34 is encountering little resistance so rapidly that the relief valve in the pump has not time enough to operate and shunt the fluid being pumped to the fluid reservoir. Accordingly, there is danger of the lines bursting, which the present construction minimizes by providing a pressure applying area x. When the load resisting the movement of pusher 34 is relatively great (on the forward stroke of pusher 34) the pressure exerted on the area x aids forward movement. However, when the pusher 34 is returning, the pressure exerted on area x opposes and operates to cushion the return movement. Further, with passages 91 and 99 and control sleeve 51 the pressure fluid directed to opposite ends of the pilot valve or spool 54 does not proceed first to the spool 54 for distribution and, if there is overtravel of the main piston, as sometimes occurs when the machine is running empty, normal operation of the parts is not disrupted.

It is to be understood that the drawings and descriptive matter are in all cases to be interpreted as merely illustrative of the principles of the invention, rather than as limiting the same in any way, since it is contemplated that various changes may be made in the various elements to achieve like results without departing from the spirit of the invention or the scope of the appended claims.

What is claimed is:

1. In combination with a pair of coaxial shafts, a

separator cage mounted on one of said shafts and a-.

pusher mounted on the other of said shafts; one of said shafts being encircled by the other and movable axially relatively thereto while rotating therewith; bearing means for the outer encircling shaft; an axially extending cylinder comprising a portion of the encircling shaft; a double-acting piston, reciprocable axially in said cylinder and comprising a portion of the encircled shaft, for shifting said shaft relatively to the enoircilng shaft; said piston having a valve seat extending within said piston; a combined distributing valve and piston shifting valve means mounted in said valve seat for movement therein and having a fluid receiving chamber; said inner shaft having a supply passage extending therethrough leading to the said valve seat; exhaust passage means for said cylinder; means for supplying fluid under pressure to said supply passage; there being passage means from said valve seat controlled by said valve means to alternately supply and exhaust fluid to and from opposite ends of said cylinder; there being also port means connecting with said fluid supply means independently of said fluid receiving chamber of the valve and receiving fluid upstream of said fluid receiving chamber leading directly to opposite end portion of said valve means; and valve control means in alignment with inner shaft member externally of said cylinder shifted automatically by the piston when said piston nears the limits of its travel in each direction to supply and exhaust fluid to said port means leading to opposite ends ,of said valve means alternately.

2. In combination with shaft means comprising a pair of coaxial shafts, one encircled by the other and movable axially relatively thereto while rotating therewith; bearings for the shaft means; a main cylinder comprising a coaxial portion of the encircling shaft; a main piston, reciprocable in said main cylinder and comprising a coaxial portion of the encircled shaft, for'shifting said shaft longitudinally relatively to the encircling shaft; said main piston having a combined ported valve seat and valve cylinder extending longitudinally within said main piston; combined ported valve seat and valve cylinder for longitudinal reciprocation therein; said inner shaft having supply passage means there being also exhaust passage a distributing valve means mounted in said means in said shaft means; said inner shaft. having-passage means leading from the ends of said piston to said combined valve seat and cylinder and from said combined valve seat and cylinder to said supply and exhaust passage means; 'there being also port means connecting with said supply passage means independently of said fluid supply chamber of the valve means leading to at least one end portion of said combined valve seat and cylinder; and valve control means in alignment with'said inner shaft member externally of said cylinder shiftable automatically when said main piston nears the end of its travel in both directions to supply and exhaust fluid through said latter port means.

3. In combination with a pair of inner and outer shafts, .one encircled by the other and movable longitudinally relatively thereto while rotating therewith; bearing means for the outer encircling shaft; a cylinder comprising a portion of the encircling shaft; a double-acting piston, reciprocable longitudinally in said cylinder and comprising a portion of the encircled shaft; for shifting said inner shaft relatively to the encircling shaft; said piston having a ported valve seat extending within said piston; a combined distributing valve and piston shifting means mounted in said ported valve seat for movement therein to control fluid supply to and exhaust from opposite ends of said cylinder; said inner shaft having a pressure fluid supply passage leading therethrough to the said valve seat; said inner shaft having radially extending surface means externally of said cylinder and a fluid distributing control member externally of said cylinder in the longitudinal path of movement of said surface means of the inner shaft; there being pressure fluid supply means leading to said control member and pressure fluid exhaust means also communicating therewith; said shafts having port means leading to opposite ends of said valve seat from said control member and communicating alternately with the fluid supply means and pressure fluid exhaust means in accordance with the longitudinal position of said control member; said control member and inner shaft surface means interengaging so that said inner shaft moves said control member in the longitudinal direction of travel of said inner shaft to position said control member.

4. The combination defined in claim 3 in which said inner shaft surface means comprises par-ts straddling a part on said control member but spaced apart a predetermined distance to provide lost motion of said inner shaft relative to said control member.

5. The combination defined in claim 4 in which an inner shaft interengaging part is movable to different predetermined positions relative tothe interengaging part on the control member.

. 6. In combination with a pair of shafts, one encircled 3 by the other and movable longitudinally relatively thereto While rotating therewith; bearing means for the outer encircling shaft; a main cylinder comprising a portion of the encircling shaft; a double-acting'main piston, reciprocable longitudinally in said main cylinder and comprising Ia portion of the encircled shaft, for shifting said shaft relatively to the encircling shaft; said main piston having a ported valve seat extending within said main piston; a combined'distributing valve and piston shifting means mounted in said ported valve seat for movement therein to control fluid supply to and exhaust from opposite ends of said main cylinder; said inner shaft having a pressure fluidsupply passage leading therethrough to the said valve seat; a longitudinally movable fluid distributing control sleeve in the longitudinal path of movement of said inner shaft externally of said main cylinder; there being pressure fluid supply means leading to said control sleeve and pressure fluid exhaust means also communicating therewith; said shafts having ports leading to opposite ends of said valve means from said control sleeve and communicating alternately with the fluid supply means shaft having a reduced rear end of a size to be received within said control sleeve to leave a fluid passage therebetween and projecting through and beyond said sleeve; said control sleeve having an internally projecting part engaged by said rear end of the innershaft after the latter has moved a predetermined distance in one direction to shift the position of the control sleeve upon continued movement of said inner shaft; and means movable on the said reduced rear end of the inner shaft to various longitudinal positions and also of a size to be received by said control sleeve to leave a fluid passage therebetween engaging said internally projecting part after a predetermined time when the inner shaft moves in the opposite direction to shift the position of said control sleeve.

7. The combination defined in claim 6 in which said rear end of the inner shaft terminates in a threaded member; and said means movable thereon comprises a stroke adjusting sleeve member threaded thereon; said outer shaft terminating in a removable cap which can be removed for ready access to said stroke adjusting sleeve.

8. The combination defined in claim 6 in which said control sleeve is exteriorly grooved to define lands thereon; and said pressure fluid exhaust means communicates with said groove; said fluid supply means leads to the interior of said control sleeve; said ports leading to opposite ends of said valve means being exposed alternately to the interior of said control sleeve and said groove; and said projecting part on said control sleeve being one of a plurality of circumferentially spaced lugs defining fluid passages between them.

9. In combination with a pair of shafts, one encircled by the other and rotating therewith; bearing means for the outer encircling shaft; a cylinder comprising a portion of the encircling shaft; a piston in said cylinder and comprising a portion of the encircled shaft, one of said shafts being reciprocable relative to the other; said piston having a ported valve seat extending within said piston; a distributing valve mounted in said ported valve seat for movement therein to control fluid supply to and exhaust from opposite ends of said cylinder; said inner shaft having a supply passage leading therethrough to the said valve seat; longitudinally movable, fluid distributing, control means in the longitudinal path of movement of said reciprocating shaft externally of said cylinder; there being pressure fluid supply means leading to said control means and pressure fluid exhaust means also communicating therewith; said shafts having ports leading to opposite ends of said valve means from said control means and communicating alternately with the fluid supply means and pressure fluid exhaust means in accordance with the longitudinal position of said control means; said control means and reciprocable shaft having engaging parts Within the length of stroke of the shaft so that said shaft moves said control means in a longitudinal direction of travel to position said control means.

10. In combination with shaft means comprising a pair of coaxial shafts, one encircled by the other and rotating therewith; means for rotating said shafts; bearing means for the shaft means; a cylinder comprising a portion of the encircling shaft; a piston in said cylinder and comprising a portion of the encircled shaft, one of said shafts being reciprocable relative to the other; said piston having a valve seat extending within said piston; a distributing valve means mounted in said valve seat for movement therein and having a fluid receiving chamber; said inner shaft having a supply passage leading to the said valve seat; exhaust passage means for said shaft means; means for supplying fluid under pressure to said supply passage; there being passage means from said valve seat controlled by said valve means to supply and exhaust fluid to and from said cylinder; there being also port means connecting with said fluid supply means independently of said fluid receiving chamber of the valve and receiving fluid upstream thereof leading to at least one end portion of said valve means; and valve control means within one of said outer and inner shafts externally of said cylinder shifted automatically when said reciprocable shaft nears the limits of its travel in each direction to supply and exhaust fluid to and from said port means.

11. In combination with shaft means comprising a pair of coaxial shafts, one encircled by the other and rotating therewith; bearing means for the shaft means; a cylinder comprising a portion of the encircling shaft; a piston in said cylinder and comprising a portion of the encircled shaft; one of said shafts being reciprocable relative to the other; said piston having a valve seat extending within said piston; a distributing valve means mounted in said valve seat for movement therein and having a fluid receiving chamber; said inner shaft having a supply passage leading to the said valve seat; means for supplying fluid under pressure to said supply passage; there being passage means from said valve seat controlled by said valve means to supply and exhaust fluid to and from said cylinder; there being also port means connecting with said fluid supply means leading to at least one end of said valve means; there being exhaust port means in said outer shaft leading from one end of said cylinder externally of said outer shaft; reservoir means communicating with said latter exhaust port means and a removable member received within said latter port means accessible at the exterior of said outer cylinder.

'12. The combination defined in claim 11 in which said exhaust port means comprises a pair of intersecting ports and said removable member comprises a threaded member having a tapered valve head extending into the juncture of said ports and adjustable to variably open the ports.

13. In combination with shaft means comprising a pair of shafts, a separator cage mounted on the front end of one of said shafts and a pusher mounted on the front end of the other of said shafts, one of said shafts being encircled by the other and rotating therewith; bearing means for the shaft means; a cylinder comprising a portion of the encircling shaft; a main piston in said cylinder and comprising a portion of the encircled shaft, one of said shafts being reciprocable relative to the other; said piston having a ported valve seat extending within said piston; a distributing valve mounted in said ported valve seat for movement therein to control fluid supply to and exhaust from said cylinder; said inner shaft having a supply passage leading therethrough to the said valve seat; fluid supply means communicating with said supply passage; said inner and outer shafts extending beyond said cylinder at their rear ends; and said reciprocating shaft having near its opposite end, and beyond the cylinder, a radial rearward facing surface area rearwardly of said cylinder communicating with said fluid supply means; said fluid supply means communicating with the rearward facing surface to aid the forward stroke of the reciprocating shaft and to cushion the return stroke of the reciprocating shaft.

14. In combination with a pair of coaxial shafts; a separator cage mounted on one of the shafts and a pusher mounted on the other of the shafts, one shaft being encircled by the other and rotating therewith; means for rotating said shafts; a cylinder comprising a portion of one of the shafts; a piston in said cylinder and comprising a portion of the other shaft, one of said shafts being reciprocable relative to the other; said piston having a valve seat extending within said piston; a distributing valve means mounted in said valve seat for movement therein and having a fluid receiving chamber; one of the shafts having a supply passage extending therethrough leading to the said valve seat; means for supplying fluid under pressure to said supply passage; there being passage means from said valve seat controlled by said valve means to supply and exhaust fluid to and from said cylinder; there being also passage means for supplying fluid to and exhausting fluid from said distributing valve Within one of said outer and inner shafts externally of said cylinder shifted automatically when said reciprocable shaft nears the limits of its travel in each direction to supply and exhaust fluid to and from said valve means.

15. In combination with shaft'means comprising a pair of coaxial shafts, one encircled by the other and movable axially relatively thereto while rotating therewith; bearing means for the shaft means; a cylinder comprising a portion of the encircling shaft; a piston, reciprocable in said cylinder and comprising a portion of the encircled shaft, for shifting said shaft relatively to the encircling shaft; said piston having a valve seat extending within said piston; first piston shifting control valve means mounted in said valve seat for movement therein and having a fluid receiving channel; said inner shaft having supply passage means extending therethrough leading to the said valve seat and a control valve chamber; exhaust passage means for said shaft means; means for supplying fluid under pressure to said supply passage means; there being passage means from said valve seat channel controlled by said valve means to supply and exhaust fluid to and from said cylinder; there being also port means, 'connecting with said fluid supply means, leading to at least one end of said valve means; second control valve means mounted in said control valve chamber and shifted automatically when said piston nears the limits of its 12 travel in each direction to supply and exhaust fluid to said port means leading to said first control valve means; and means exerting a pressure on the wall of said chamber to prevent drifting of said second control valve means. 16. The combination defined in claim 15 in which said second control valve means is tubular to pass fluid under pressure and the means exerting a pressure comprises an opening in the wall of said second control valve means to permit the fluid ;to reach and exert a pressure on the wall of the chamber for the second control valve means.

References Cited in the file of this patent UNITED STATES PATENTS 203,511 Vaile May 7, 1878 1,944,391 Altpeter Jan. 23, 1934 2,232,770 Buddeberg Feb. 25, 1941 2,331,959 Buddeberg Oct. 19, 1943 2,597,443 Broughton May 20, 1952 2,738,770 Granzow Mar. 20, 1956 2,748,752 Baghuis June 5, 1956 2,768,611 Anderson Oct. 30, 1956 2,820,436 Ruegg Jan. 21, 195 8 2,899,065 Irving Aug. 11, 1959 Ortman et a1 May 3, 1960 

1. IN COMBINATION WITH A PAIR OF COAXIAL SHAFTS, A SEPARATOR CAGE MOUNTED ON ONE OF SAID SHAFTS AND A PUSHER MOUNTED ON THE OTHER OF SAID SHAFTS; ONE OF SAID SHAFTS BEING ENCIRCLED BY THE OTHER AND MOVABLE AXIALLY RELATIVELY THERETO WHILE ROTATING THEREWITH; BEARING MEANS FOR THE OUTER ENCIRCLING SHAFT; AN AXIALLY EXTENDING CYLINDER COMPRISING A PORTION OF THE ENCIRCLING SHAFT; A DOUBLE-ACTING PISTION, RECIPROCABLE AXIALLY IN SAID CYLINDER AND COMPRISING A PORTION OF THE ENCIRCLED SHAFT, FOR SHIFTING SAID SHAFT RELATIVELY TO THE ENCIRCLING SHAFT; SAID PISTON HAVING A VALVE SEAT EXTENDING WITHIN SAID PISTON; A COMBINED DISTRIBUTING VALVE AND PISTON SHIFTING VALVE MEANS MOUNTED IN SAID VALVE SEAT FOR MOVEMENT THEREIN AND HAVING A FLUID RECEIVING CHAMBER; SAID INNER SHAFT HAVING A SUPPLY PASSAGE EXTENDING THERETHROUGH LEADING TO THE SAID VALVE SEAT; EXHAUST PASSAGE MEANS FOR SAID CYLINDE; MEANS FOR SUPPLYING FLUID UNDER PRESSURE TO SAID SUPPLY PASSAGE; THERE BEING PASSAGE MEANS FROM SAID VALVE SEAT CONTROLLED BY SAID VALVE MEANS TO ALTERNATELY SUPPLY AND EXHAUST FLUID TO AND FROM OPPOSITE ENDS OF SAID CYLINDER; THERE BEING ALSO PORT MEANS CONNECTING WITH SAID FLUID SUPPLY MEANS INDEPENDENTLY OF SAID FLUID RECEIVING CHAMBER OF THE VALVE AND RECEIVING FLUID UPSTREAM OF SAID FLUID RECEIVING CHAMBER LEADING DIRECTLY TO OPPOSITE END PORTION OF SAID VALVE MEANS; AND VALVE CONTROL MEANS IN ALIGNMENT WITH INNER SHAFT MEMBER EXTERNALLY OF SAID CYLINDER SHAFT AUTOMATICALLY BY THE PISTON WHEN SAID PISTON NEARS THE LIMITS OF ITS TRAVEL IN EACH DIRECTION TO SUPPLY AND EXHAUST FLUID TO SAID PORT MEANS LEADING TO OPPOSITE ENDS OF SAID VALVE MEANS ALTERNATELY. 